Electric-iron thermostat



Jan. 9, 1951 A. BATE 2,537,808

ELECTRIC IRON THERMOSTAT Filed Dec. 11, 1946 /7V7 I F 1 21" 2 2 4/ /23/45 INVENTOR. ALAN BATE Y inwthe spirit of the inventionand-tlie scope (ifthe Patented Jan. 9, 1951 UNITED PAT E N'l? 253L808:

IJEGTRICJRQN THEBMQSTAT' AlanflBate, R'iverton; .Conn., assignorzto 'llli'e wim sted Hardware Manufacturing; Gompanyt Win--- ired C n 7 e rnor m Q G nnec 'cut uc uo pe e pe; 11, 1946, serum-b; 715,5 1 Z CIaims; (c1. zit-+25);

This invention relates to new" and useful im provexnents in=thermostaticcontrolsand 'has par-- ticular relation to thermostatio controls formingpa'rt's of electri'ca-l appliances. I

The objects and advantages of the invention will-" become apparent' from'a consideration of the' following detailed description taken in connectionwith the accompanying drawing wherein satis factory embodiments of the invention are sl'io.wn: However;- itlis to be'understood that the'invention isnot 'limited to thedetails disclosedildutiincliids all such variations and modifications as fall w' appended cl'aimss In the-drawing 12 is: a" longitudinal' sectional-' view of an electric-iron and showing an application of -the invention;

Fig: 2eis afldetailed' plan viewvtak'enas along theplane of tl'ie line 2'-2 'of Fig: 1"; 1

Fig; 3 1s a detail elevational viemshowing the thermostatic: control in association with a por tionzof the sole plate only ofth'e ironof- Fig-z 1;

Fig. .4 isxazviewxsimilar-to Figs 3-" an'd showing zumodification;

Figs 5 'is a'similar-view sliowima-iurthermodfl fication; and

6zis aisimilarzview showing yet another modification While 1 the: control of the invention" has other-- applications; itl issherein specificallydisclosed in relation: to. e an electric sadi'ronu Thus, the drawing; and referring at fi'rst' more particularly to;:l' .igs.; l; 2' and :3; at It] is generally indieaf ed a; sadigonlincluding a-lsole plate I I and a shell or casing ;l 2: Against the inner side ofthe sole pl c is am electrical h'eating device .01" elemerit 13 maintained: against: the sole wplate as by a filler bloclev H but separated from said block by air electrical and heat insulator 15. r

Contact: prongs. 01: pins 16; adapted fon use=- with; -any.;of ithecusualheater plugs (not shown) are mounted or pass th rcugh'and are insulated fnormazurear wall portion I51 of the shell -I-2. As: shown; these prongs-tv arecinsulated byseparators .alBzandsare clamped to the wall portioni 1 between nuts l9 and 20. Any suitable guard dcvice 21 maybe iarranged iabout the prongs I69 At. its inner side, thesole plate H "is pr-ovided witlmiaapairzof sockets 'or recesses =2Z' apd 23I A 111E324, having a fiaizedor: dove tailed head' portion; has such. head-portion disposedin 'the-socket on a'ecessizz and: then portion-sot the soleplate'arw pinned over against thisiheadiportiongi asat- ZW- whereby'ithedugtis maderigidtwith the sole plate. 66

therecess and has "portions of- 'tlie' sow'mapes t: vpinnediovfagainst it as at z -l wnei'ety' awayfromwlie arrn and th A move-iadownwardlyzoreawayl from' -tlie-"arm 3 3'? adjusting-s' sciew fli extends through the 'upper' side oi "'the s hell l l 2 and adaptedto be turned" by a handle 315 At its mne-rena this screw carries an electrical insulating button or' button; like part 38 Ii'orma 1Iyengaging-'- the arm toward the free encgl-ofthelatter; Turning of'" the handle =3! 1 in'- one direction the other threads -thescrew* 3B iiiwardly' or'out wardly to shift 1 the free endportion of tiiearin 33itoward the arm 35 rto 'p'rmiitsuch' free end portion'of the arnfl3- to novje'away fromthearin" 35. 0hit sinner or' underside; tlfe arm'ii'towa 111* its free end carries=a contact"b1itton 319: S" larly; toward -its-iree end; the arm 3'5carri contact-buttom 40% However; armas extendsa substantialdistance beyo'nd'its button 40 and such extended end portion is' norm'ally' inem gagement with "a button-'41 of insul atin'g material carriediomthe'upper sidebfthe midportion' or substantially the rnidportion' of a metallic ei'e* ment: 4?; bowed i or otheiWise" pward13 o1'--- outfwai'dlyoffset intermediateits eridsf Element .xdz is' p efera bly of an alloy of "m'kel" steel, thecalzloy'iitcludiiigi2 amen ma teriah ior purposef has advantages that 42 is mounted by being bowed and having its free ends located in notches 43 and 44 in the opposed faces or edges of the lugs 24 and 2B. These lugs are so spaced with relation to the length of the element 42 that the latter, in spite of its tendency to assume a flat position, is held in a bowed position between the lugs. i I

From Figs. 1-3, it will be clear that the bowed element 42 supports the outer end of the arm 35 limiting the extent to which the contact button 40 may move away from the contact button 39. In these figures, the parts are shown" positioned with the button 40 engaged with the button 39,

or in closed circuit relation therewith, whereby the circuit to the heating element 13 is closed and this situation obtains when the sole plate II I is below the desired temperature.

It will be understood that the sole plate, at this time being below an ironing temperature, has contracted and contraction of the sole plate resultedin movement of the lugs 24 and 26 toward one another bowing or increasing the degree of curvature of the element 42. The circuit to the heatingelement being closed, the sole plate will increase in temperature. sole plate expands and the lugs 24 and 25 are moved apart or from one another permitting the element 42 to assume a more flattened condition whereby its central portion will be lowered permitting the outer portion of arm 35 to move inwardly separating its contact button 40 from the contact button 39whereupon the circuit to the element I3 is again opened.

In connection with this operation, it will be understood that the material of the sole plate I i has a much higher coefficient of expansion than has the material of the element 42. Further, it will be understood that the button 4! working against the extended portion of the arm 35 or that portion beyond the contact 45, acertain leverage is obtained for shifting of the contact.

40 into engagement With the contact 39.

Asherein shown, the inner ends of the arms 33 and 35 are mounted on the stud 38 but are not in electric engagement therewith. These arms are insulated from the lug ZBand from one another as by means of insulating washers 45,

and are clamped in position by a nut 46 threaded down against the washers and arms on the stud A'simil-ar nut 41 serves to anchor the extension 32 of'arm 33to one of the prongs l6. 7

From the foregoing description it will be understoodthat the prongs It being connected with,

a source of electrical energy, the resistance element l3 will be energized as long as the contact buttons 39 and'45 are engaged. .These buttons are permitted to separate only on flattening of the element 42. inbowed condition by the lugs 24 and 26 until the sole plate H has expanded a predetermined amount due to the application of heat. The sole plate temperatureat'which the button 49 moves away from the button '39, is determined by the position of the latter. Suchpos ition is adjustable] being controlled by manipulation of the screw 36 so as to control the position of the button 39 with respect to the button 40 and thus to control the distance the button 43 must move to become engaged with or disengaged from the button 39.

'It will be clear that I have an extremely simple arrangement for the purpose intended, the same merely involving the contact button carrying arms 35 and 33 and the bowed element 42. While this element itself is not a bimetallic strip, the

As this occurs, and the However, such element is heldv ase'aso difference in the coefficient of expansion of the material of the sole plate with respect to the material of the element 42 provides for the bowing and flattening of the element.

Fig. 4 shows a slight modification wherein a portion of the sole plate of an iron is designated 50 and has rigid therewith a pair of spaced lugs 5! and-52 fastened thereto in'the manner previously described with respect to the lugs 24 and '26. Lug 5| carries a short threaded stud 53 while the lug 52 carries a longer threaded stud 54 which is the same as the stud 28 previously dexscribed. In this figure, the arms 33 and 35 are again employed and they are provided with the contact buttons 39 and 40.

i The essential difference between the structure of Fig. land that of Figs. 1-3 resides in the fact that in the modification an element 55 has periorated ends disposed over the studs 53 and 54.v This element is thus anchored to the studs and.

a nut 56 retains the element or stud 53 while the;

nut above described accomplishes the same:

purpose for that end of the element on the stud;

54. Element is of the material of the element- 42 and while the element has a normal tendency to assume a flat condition, it is held in bowed condition by being anchored on the studs 53 and. Intermediate its ends this element carries; an insulating button 51 correspondingwithand;

for the purpose of the button 4i previously described.

With this construction, it will acres are; as the sole plate 55 is heated and expands, the;

studs 53 and 54 will be moved in ,directionsaway' i ,Now, as the sole plate heatsand from one another permitting the bowed or oiiset element 55 to flatten somewhat. In fact, as the,

studs are thus moved outwardly and pull theends; of element 55 apart, the latter is flattened, somewhat, regardless of whether it has a normal tend-.

ency to seek a fiat condition. This permits the arm 35 to move downwardly carrying its contact button 40 away from the contact button 39. of the arm 33. On the sole plate cooling, it vconone another and causing a higher degree of curvature in the element 55 whereby the arm .35 will.

be flexed upwardly to engage its contact button 40 with the contact button 39 again closing a circuit through the resistance element i3.

Referring now to the modification of.Fig. 5,. Where the parts there are the same as previously: described, they have been given the same refers. In this construction, the lugs 5|. ,and 52 are again made fast to the sole plate .50 but the arm. 35 and its contact button 40 are. omitted, although the arm 33 and .its contact. .v button 39 are employed. Now, the bowed or off.- set element 55 carries a contactbutton 60 adapted. to come into circuit closing relation with the conence numbers.

tact button 39. To this end, a lead or extension 5| from the element 55 is connected in the, circuit For this type of. construction, the anchored ends of the element .1. v 55 are insulated from the lugs.5,l and v52 and the studs 53 and 54 by suitable di-electric construc..:

of the resistance element l3.

tions 62. a

In the modification, the contact buttonfifl-isi shown engaged with the contact button 39. and therefore it will be understood that the soleplate 50 15 below ironing temperature. the element 55 is inbowed condition as its end.

portions move inwardly with the studs 53 and 54 on cooling of the sole plate.

studs 53 and 54 will be shifted from one another At this time,

expands, the

aeemsosand will permit?'offlatteningxofthe element 55 wherebyitsv button. Bil. will be carried from .engagement with thebutton' as opening the circuit through the resistance heating element I3. In the particulanconstrnction of Fig. 5, it is noted that a minimum of elements are used and yet a fully operative device for, the intended pulfpose'has been provided.

In Fig. 6, the construction is somewhat similar to that in Figs. 1-3 with the exception that the lug or head. is entirely omitted. In this figure many'parts are the same as those in Figs. 1-3 and'have been given the samereference numbers. The modification consists essentially in that a bowed or offset element 19 of high content nickel steel (of the material of the element 42) has flattened end portions H and 12 which are we1ded or in any other similar manner made rigid with the inner side of the sole plate I I.

Element 70 includes an insulating button 13 engaging the underside of the arm 35 inwardly of the free end thereof. With this construction,

it will be clear that as the sole plate H expands, the ends of element 1!! are drawn apart and the latter thus becomes somewhat flattened and permits the arm 35 to move downwardly carry ing its contact button 49 away from the contact button 39 of the arm 33 and thus opening the circuit of the heating element l3.

On cooling ofthe sole plate H, the anchored ends H and E2 of element it will be carried toward one another as the sole plate contracts and thus additional bow imparted to the element It whereby its insulating button 13 pushing upwardly on the arm 35 will bring the contact button 40 into engagement with the contact button 39 to again close the circuit to the element It. This is the condition of the parts as seen in Fig. 6.

In this construction, due to the fact that the button 13 engages the arm 35 between the anchored end of the latter and the contact button 48, there is a difference in the leverage over that of the constructions of Figs.'l4. However, the difference is not of material importance. In Fig. 6 the head or lug 26 and its stud 28 have no part in the mounting of the element 18 but they do serve the other purposes illustrated in Fig. 1.

In the various modifications shown the bowed element, when in a fiat condition, is of greater length than the distance which may separate its ends under any useful expansion of the sole plate.

For example, with the construction of Figs. 13, the lugs 24 and 26 never move apart sufficient to permit of the element 42 assuming a fiat condition. There is always some compression of the element so that it constantly is bowed upwardly to some extent whereby on contraction of the sole plate it is further bowed upwardly. ,It is never permitted to assume a condition where contraction of the sole plate might result in bowing of the element downwardly. Further, since it is always under some compression, it will not drop out of place in the assembly.

In the constructions of Figs. 4 and 5, where the ends of the element 55 are disposed over the studs 53 and 54, the distance along the element when fiat, between the perforations in the element for the accommodation of said studs, is greater than the distance between the studs in a highly expanded condition of the sole plate and even under a condition where the plate would be too hot for use in ironing. Clearly, the

6 same condition prevails with the construction ofFig.6. Thus, it will be understood that in all thefigures, the bowed element is of such length and is so, anchored and constructed that it never assumes an actual flat condition, the operation of the switch involving merely a variation of the degree of curvature of the element as it moves toward a flat condition on expansion of the sole plate and as its degree of curvature is increased on cooling of'the sole plate.

From the foregoing description it will be clear that in each of the several forms herein dis-- closed, the bowed or offset element has its ends anchored to the sole plate. Thus, in Figs. 1-5 the element is anchored to the sole plate through the instrumentality of the lugs and studs. In. Fig. 6, the element is anchored to the sole plate bywelding, soldering, or the like. difference in the coeflicient of expansion of the bowed 0r oifset element and the sole plate, these two parts together form a bimetallic construction controlling opening and closing ofthe switch for the circuit of the heater I3.

Where in the description and in the following claims the element variously numbered 42, and 76 is described as bowed it will be understood that the same is not necessarily a true are. The word bowed as used herein is intended to cover any offset or bulged structure which tends to flatten as the plate or plate-like portion expands on heating and tends to bow or bulge or otherwise increase in height when such plate or plate-like portion contracts as it suffers a drop in temperature. Thus, for example, the structures 42, 55 and 10 may have angular bends and for the purpose of the present disclosure and the appended claims be bowed.

Having thus set forth the nature of my invention, what I claim is:

1. In a sadiron, a sole plate, an electrical heating element overlying said sole plate for heating said sole plate, said heating element having a gap therein exposing an area of the top of said sole plate at about the mid-portion thereof, a pair of positioning elements secured to said sole plate and spaced apart lengthwise thereof, each positioning element having clamping means, said positioning elements being located wholly within said gap in spaced relation to said heating ele- V ment, an upwardly bowed strip member securely fastened at its opposite ends to said positioning elements by said clamping means and disposed wholly within the area defined by said gap and spaced from said heating element, said strip member consisting of a nickel-iron alloy having a substantially uniform thermal coefiicient of expansion throughout a range of temperatures up to at least 600 F., said coefiicient of expansion being less than that of the sole plate, and switch means for opening and closing a circuit to said heating element, said switch means being controlled by said bowed member to open and close in response to increase and decrease of the temperature of said sole plate.

2. In a sadiron, a sole plate, an electrical heat- 7 ing element for heating said sole plate, said heating element having a gap therein exposing an area of the top of said sole plate at about the mid-portion thereof, a pair of threaded studs secured to said sole plate and spaced apart lengthwise thereof, said studs being located wholly within said gap in spaced relation to said heating element, an upwardly bowed strip member having apertures in its opposite ends receiving said studs,

Due to the a and threaded members to securely fasten said strip member and studs together, said strip memher being disposed wholly Within the area defined by said gap-and spaced from said heating element, said strip member consisting of a nickeliron alloy having a substantially uniform thermal coefficient of expansion throughout a range of temperatures up to at least 600 F., said coefficient of expansion being less than that of the sole plate, a pair of relatively movable, normally spaced apart switch contacts carried by one of said studs and insulated therefrom, means connecting said contacts in a circuit with said heating element, and insulating means mounted at the mid-portion of said strip member and bearing against one of said switch contacts to engage and disengage said contacts in response to variation in the temperature of said sole plate.

ALAN BATE.

8 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

